New SLK: slicker, sharper

Mercedes-Benz has sharpened up its SLK sportscar range. Restyled inside and out, with new underpinnings and an all-new range of engines, the new SLK is promised to take "driving pleasure and open air enjoyment to a new level". Back in the real world there's little doubt the new cars are faster, more wieldy, but also more economical than ever before.

Based on the same platform that underpins Mercedes-Benz's all-important C-Class, the new SLK benefits from the technology avalanche that has fallen upon that model in its latest update. In essence the new W172 series SLK has leapfrogged one and a half generations of C-Class to share its key component sets with the very latest C.

For the end user that translates into new turbo direct injected 1.8-litre four-cylinder and 60-degree direct-injected 3.5-litre V6 petrol engines, and Mercedes' latest 7G-TRONIC Plus seven-speed automatic transmission as standard equipment. It also sees the SLK range available with Benz's new Dynamic Handling Package which features electronically controlled dampers and a Sport setting that also affects steering, throttle and gearbox characteristics.

In addition to the Dynamic handling Package, two conventional suspension set-ups are offered -- standard and a lower and firmer sports setting. In Australia at least the Sport setting will likely be the default.

Safety equipment too has been bolstered thanks to the link with the C-Class. The new SLK features Presafe anticipatory occupant protection system with PreSafe Brake autonomous braking to help reduce low-speed tail-enders. The same drowsiness detection system as pioneered in the W212 E-Class makes an appearance and Speed Limit Assist, which uses navigation information and a windscreen mounted camera to indicate detected speed limits to the driver, can be optioned along with adaptive cruise control.

The exact mix of safety equipment that is destined to be standard in Aussie SLK models is still to be determined.

But it's not just C hand-me-downs that are the highlights of the new SLK. The SLK pioneered the Airscarf neck level heating system in the second generation SLK in 2004; now the flip-top roadster is bringing an innovative adjustable glass roof to market.

Magic Sky Control is one of three versions of the trademark folding vario-roof hardtop offered on the new generation SLK. It uses a glass roof panel that can change its opacity (and colour) with the alteration of electrical current to vary the amount of light that can enter the cabin.

We can report that in the relatively benign light at the start of a northern hemisphere spring it worked well (and Benz claims testing in Death Valley showed its efficiency at reducing cabin heating) but we'll wait to see how it copes with the height of an Aussie summer before we tick the box.

Standard will be a body-coloured folding roof. A conventional tinted glass panel roof is also an option. All versions can be lowered or raised in under 20sec claims Mercedes-Benz. Meantime, top down serenity is promised thanks to a choice of conventional draught stoppers or a new optional pivoting system that is permanently attached to the headrest/rollover hoops and simply rotates into place.

Featuring a dose of SLS Gullwing in its new face, the SLK looks more masculine and substantial in its latest iteration. It shares no panels with its predecessor and although longer it rides on the same wheelbase. Track is up front and rear. The new car is more efficient aerodynamically.

The cabin too takes a leaf out of the Gullwing book. The dash features more than a hint of the flagship AMG supercar in its strong horizontal orientation and four eyeball vents look like they've come straight from Affalterbach. The SLK's centre console is also very reminiscent of the SLS. Overall trim materials have taken a considerable step upmarket.

On the road from the rear quarter the new SLK looks more SL than SLS -- a blessing given the rather controversial backside of the supercar. Whatever your impression, there's little doubt in our mind the new SLK will appeal to a wider audience.

While predominately a steel structure (Mercedes sportscar will move to an aluminium platform in the next generation of SL), alloy has been used for key components in the new SLK.  The bonnet and front wings are of aluminium, as are the dashboard cross-members and sections of the vario-roof.

A carbon-reinforced plastic structure is used for the rear cockpit bulkhead. Overall, Mercedes claims to have increased rigidity yet reduced the bodyshell's weight by around 13 kilograms. Indeed, the new SLK is claimed to be up to 70kg lighter than its predecessor depending on the model -- this is despite additional equipment and a move to the seven-speed auto.

The sportiness of the SLK is augmented by the sexing up of the engine noise in both four and six-cylinder versions.

The turbo fours benefit from a sound generator which channels selected noise frequencies into the cabin from the inlet manifold. And it works well, delivering some obvious but not intrusive 'growl' to the cockpit. With a resonant 'boof' from the wastegate and exhaust on full-throttle upshifts, there's just a hint of hot hatch for extra spice.

In the V6 a retuned exhaust has more than a hint of the exotic to the exhaust note when compared to the hushed tones the same engine emits in the C-Class saloon.

All variants get steering wheel paddles with which to stir the 7G-TRONIC tranny into life.

When the SLK arrives locally mid-year, three variants will be offered.

The SLK 200 BlueEFFICIENCY and SLK 250 BlueEFFICIENCY pump out 135kW/270Nm and 150/310 and record 0-100km/h times of 7.0 and 6.6sec respectively. Fuel economy is 6.1L/100km for the 200 in NEDC Combined testing. The 250 is just 0.1L/100km thirstier.

The SLK 350 BlueEFFICIENCY's V6 engine is rated at 225kW/370Nm and trims a full second from the fastest four's time to 100km/h. Fuel economy is still a very respectable 7.1L/100km.

All three SLKs will benefit from the new 'ECO' auto stop start system.

A turbodiesel SLK will be launched for the first time later this year. It will feature a version of the same powerplant that impresses in the C 250 CDI. With over 500Nm in some variants it should be an interesting drive, although Mercedes-Benz Australia is not sure our market is ready for a diesel sportscar just yet. AMG's naturally aspirated V8 SLK 55 will debut globally towards the end of 2011 and arrive Down under in Q1 2012.

We sampled the new SLK on the some of Europe's most challenging roads on the volcanic island of Tenerife. Tight, twisty and at times incredibly narrow, they didn't necessarily show the SLK at its best.

When the road was smooth the SLK was predictable and wieldy but it didn't display the limpet-like levels of grip you'd expect from a top line sportscar. As the roads opened up so did the SLK and our smiles -- as a fast GT car the car has strong credentials.

For once, it's probably the four-cylinder car that's the pick -- at least the 250, we didn't get to drive the SLK 200. Nicely balanced, the turbo 250 has enough go to get your attention and thanks to the acoustic tricks under the bonnet has an engaging engine note. The 7G-TRONIC matches better with the four than the six in this model.

Alas on the bumps and tight stuff that made up more of the 260km test loop, even the 250 is not totally convincing. In tight uphill corners it scrabbles for power-down traction and it's only when you resort to full manual mode on the auto that progress becomes as fluid and predictable as it should be. There are autos that perform better in this sort of driving than the Benz's.

Look out for our full launch coverage of the new SLK range.

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